NEBRASKA, United States (Reuters) — U.S. investor Warren Buffett, speaking at a campaign rally for Democratic presidential candidate Hillary Clinton, challenged Republican Donald Trump on Monday (August 01) to release his tax returns. Trump has said he would not release his returns until the Internal Revenue Service has completed an audit. “Now I’ve got news for him, I’m under audit too and I would be delighted to meet him anyplace, anytime, before the election,” said […]